Blackpowder cylinder/barrel gap

herb · February 17, 2010, 06:04 PM

I know how to reduce gap by removing metal from barrel pin and barrel lug. I've ended up with a new gun with .001 clearance which causes cocking problems after firing a dozen rounds. Do you shim with barrel pin & lug.?? I don't like the idea of over 35 gr load in steel 44 which a friend suggested. Don't need a hand gernade.

hickstick_10 · February 17, 2010, 06:50 PM

First of all please read http://www.oldwestgunsmith.com/mybooks/g2.htm it used to be available from Track the wolf muzzloading supply.

Your gap is to small, and fouling has built up causing it to bind, its really easy to take metal off, but putting it back on is another matter, a nice solution would be to take it to a competent gunsmith or machinist and have him trim a couple thou off of the cylinder face.

Assuming you have a colt clone, it will easily handle all the 3 fg BLACK POWDER you can fit in the chamber. Your accuracy may be poor with maximum loads though.

madcratebuilder · February 19, 2010, 07:14 AM

.001 is way to tight. .008 is the recommended clearance on Colt revolvers. Take some material off the breech end of the barrel. You can fill the chambers with black powder and not over pressure your revolver, you well not have a the best accuracy, you well have a lot of smoke and flame.

Gatofeo · February 20, 2010, 11:38 PM

The Colt design employs a wedge to hold the barrel assembly against the cylinder. Why can't you gently tap the wedge out a wee bit, until the cylinder revolves a little more free?
I use an akin method when assembling my Colt revolvers.
With a clean revolver (no fouling on cylinder face or rear of barrel), I tap in the wedge while rotating the cylinder. When I reach the point that the cylinder begins to bind, I stop.
Then, I turn the revolver over, again while rotating the cylinder, tap the wedge OUT a little. Just enough to where the cylinder rotates freely again.
This is what I consider the "sweet spot" of the Colt design.
If you can push the wedge out with your thumb, it's far too loose.
You may have to remove the screw above the wedge, to tap it in far enough, but that typically isn't required until you've fired a thousand rounds or more.

So, can't you just tap the wedge out a little, to increase the cyilnder/forcing cone gap?

Doc Hoy · February 21, 2010, 06:48 AM

On some of my pistols I can use the wedge screw as a guide for how far the wedge has to go into the slot. Doesn't work for all of them.

Suiftwater · February 21, 2010, 06:52 PM

Hello Gatofeo,

I think these play with the wedge is only a characteristic of our non original Colt revolver copies, note the position of the barrel and frame change after move a little bit the wedge and that spoils the precision of the gun.

Look at this drawing published in a spanish forum (sorry for the spanish text), and note the diference between original and real Colt revolvers, first revolver drawing (original Cot revolver), second revolver drawing (typical italian copy):

[URL=http://imageshack.us]

[/

As you can see, original Colts have a sole position for the wedge, italian copies usually allow more game with the wedge position, this is because the cheaper construction in the actual copies.

Regards

madcratebuilder · February 22, 2010, 09:31 AM

If your using the wedge to control barrel gap you have a short arbor. The arbor should bottom in the lug and the wedge pulls it tight and does not change barrel gap.

herb · February 22, 2010, 06:16 PM

Last two posts make sense!

Suiftwater · February 23, 2010, 05:50 PM

This is not a black powder revolver analysis, however interesting conclusions:

http://findarticles.com/p/articles/m.../?tag=untagged

Finally, do not be obsessed to much about the gap dimension.

Regards

logeorge · February 23, 2010, 08:11 PM

So how come we can't make a plug to fill the gap, trim and try until the barrel-to-cylinder gap is correct, then glue it in place with epoxy or Loctite? I never thought about it until I saw this thread. I'll try it on mine and see how it works out! (If I ever get decent weather and time to get to the range at the same time!) I'll let you know what happens. One of those " Why didn't I think of that?" moments. L. O. G.

mykeal · February 23, 2010, 08:30 PM

Lots of people have in fact installed 'shims' at the end of the arbor to make up for this deficiency. I don't find that it matters in any of my guns, so far, or I'd probably have done so myself.

madcratebuilder · February 24, 2010, 10:58 AM

Quote:

Finally, do not be obsessed to much about the gap dimension.

+1

If the gap is tight, .003 or less you may have fouling that well interfere with the cylinder rotating. Excessive gap allows more gas to escape and you well have a minor drop in velocity, that's no big deal with me.

I am anal retentive about arbor fit. It's is addressed on every revolver I buy before it is fired. Benefits are less wear and tear on the wedge and wedge slots. The wedge stays tight and I have no cylinder drag. Possibly a minor increase in accuracy, you would need a gun vise to know for certain.

For me, knowing that the revolver is properly fit I can concentrate 110% on shooting.

Noz · February 24, 2010, 12:49 PM

http://www.cascity.com/forumhall/ind...c,25009.0.html

Go here for complete instructions on tuning a Colt style Pietta revolver.

The same author has written a similar article on the Uberti pistols. The Ubertis are the ones with the poor arbor fit.

herb · February 24, 2010, 05:31 PM

madcratebuilder. right on! I want GAP CORRECT also.

February 17, 2010, 06:04 PM	#1
herb Member Join Date: February 6, 2010 Posts: 56	Blackpowder cylinder/barrel gap I know how to reduce gap by removing metal from barrel pin and barrel lug. I've ended up with a new gun with .001 clearance which causes cocking problems after firing a dozen rounds. Do you shim with barrel pin & lug.?? I don't like the idea of over 35 gr load in steel 44 which a friend suggested. Don't need a hand gernade.

February 20, 2010, 11:38 PM	#4
Gatofeo Senior Member Join Date: October 1, 2004 Location: Remote Utah desert Posts: 224	The Colt design employs a wedge to hold the barrel assembly against the cylinder. Why can't you gently tap the wedge out a wee bit, until the cylinder revolves a little more free? I use an akin method when assembling my Colt revolvers. With a clean revolver (no fouling on cylinder face or rear of barrel), I tap in the wedge while rotating the cylinder. When I reach the point that the cylinder begins to bind, I stop. Then, I turn the revolver over, again while rotating the cylinder, tap the wedge OUT a little. Just enough to where the cylinder rotates freely again. This is what I consider the "sweet spot" of the Colt design. If you can push the wedge out with your thumb, it's far too loose. You may have to remove the screw above the wedge, to tap it in far enough, but that typically isn't required until you've fired a thousand rounds or more. So, can't you just tap the wedge out a little, to increase the cyilnder/forcing cone gap? __________________ "And lo, did I see an ugly cat. Smoke. Brimstone. Holes in parchment. And this ugly cat was much amused." --- The Prophesies of Gatodamus (1503 - 1566)

February 21, 2010, 06:48 AM	#5
Doc Hoy Senior Member Join Date: October 24, 2008 Location: Naples, Fl Posts: 5,440	Fellas, On some of my pistols I can use the wedge screw as a guide for how far the wedge has to go into the slot. Doesn't work for all of them. __________________ Seek truth. Relax. Take a breath.

February 21, 2010, 06:52 PM	#6
Suiftwater Junior Member Join Date: February 15, 2008 Location: Madrid, Spain Posts: 14	Hello Gatofeo, I think these play with the wedge is only a characteristic of our non original Colt revolver copies, note the position of the barrel and frame change after move a little bit the wedge and that spoils the precision of the gun. Look at this drawing published in a spanish forum (sorry for the spanish text), and note the diference between original and real Colt revolvers, first revolver drawing (original Cot revolver), second revolver drawing (typical italian copy): [URL=http://imageshack.us][/ As you can see, original Colts have a sole position for the wedge, italian copies usually allow more game with the wedge position, this is because the cheaper construction in the actual copies. Regards Last edited by Suiftwater; February 21, 2010 at 07:03 PM.

February 23, 2010, 08:11 PM	#10
logeorge Member Join Date: December 24, 2007 Location: Ardmore, AL Posts: 68	Gap at end of cylinder arbor. So how come we can't make a plug to fill the gap, trim and try until the barrel-to-cylinder gap is correct, then glue it in place with epoxy or Loctite? I never thought about it until I saw this thread. I'll try it on mine and see how it works out! (If I ever get decent weather and time to get to the range at the same time!) I'll let you know what happens. One of those " Why didn't I think of that?" moments. L. O. G. Last edited by logeorge; February 23, 2010 at 10:04 PM.

February 17, 2010, 06:50 PM	#2
hickstick_10 Senior Member Join Date: August 8, 2009 Posts: 477	First of all please read http://www.oldwestgunsmith.com/mybooks/g2.htm it used to be available from Track the wolf muzzloading supply. Your gap is to small, and fouling has built up causing it to bind, its really easy to take metal off, but putting it back on is another matter, a nice solution would be to take it to a competent gunsmith or machinist and have him trim a couple thou off of the cylinder face. Assuming you have a colt clone, it will easily handle all the 3 fg BLACK POWDER you can fit in the chamber. Your accuracy may be poor with maximum loads though.

February 19, 2010, 07:14 AM	#3
madcratebuilder Senior Member Join Date: November 2, 2007 Location: Northern Orygun Posts: 4,923	.001 is way to tight. .008 is the recommended clearance on Colt revolvers. Take some material off the breech end of the barrel. You can fill the chambers with black powder and not over pressure your revolver, you well not have a the best accuracy, you well have a lot of smoke and flame.

February 22, 2010, 09:31 AM	#7
madcratebuilder Senior Member Join Date: November 2, 2007 Location: Northern Orygun Posts: 4,923	If your using the wedge to control barrel gap you have a short arbor. The arbor should bottom in the lug and the wedge pulls it tight and does not change barrel gap.

February 22, 2010, 06:16 PM	#8
herb Member Join Date: February 6, 2010 Posts: 56	Last two posts make sense!

February 23, 2010, 05:50 PM	#9
Suiftwater Junior Member Join Date: February 15, 2008 Location: Madrid, Spain Posts: 14	This is not a black powder revolver analysis, however interesting conclusions: http://findarticles.com/p/articles/m.../?tag=untagged Finally, do not be obsessed to much about the gap dimension. Regards

February 23, 2010, 08:30 PM	#11
mykeal Senior Member Join Date: October 8, 2006 Location: Northern Michigan Posts: 2,772	Lots of people have in fact installed 'shims' at the end of the arbor to make up for this deficiency. I don't find that it matters in any of my guns, so far, or I'd probably have done so myself.

February 24, 2010, 12:49 PM	#13
Noz Senior Member Join Date: February 25, 2009 Posts: 643	http://www.cascity.com/forumhall/ind...c,25009.0.html Go here for complete instructions on tuning a Colt style Pietta revolver. The same author has written a similar article on the Uberti pistols. The Ubertis are the ones with the poor arbor fit.

February 24, 2010, 05:31 PM	#14
herb Member Join Date: February 6, 2010 Posts: 56	madcratebuilder. right on! I want GAP CORRECT also.